"I'm sorry to say that there has been an accident. Happy was run over and is very sick at the hospital. Even now they are performing a big operation on her."

The Daddy let out a wail. "Aiee! My daughter! My little baby Happy!"

A good actor, thought Mma Ramotswe, unless... No, she preferred to trust Happy Bapetsi's instinct. A girl should know her own Daddy even if she had not seen him since she was a baby.

"Yes," she went on. "It is very sad. She is very sick. And they need lots of blood to make up for all the blood she lost."

The Daddy frowned. "They must give her that blood. Lots of blood. I can pay."

"It's not the money," said Mma Ramotswe. "Blood is free. We don't have the right sort. We will have to get some from her family, and you are the only one she has. We must ask for some blood."

The Daddy sat down heavily.

"I am an old man," he said.

Mma Ramotswe sensed that it would work. Yes, this man was an impostor.

"This is why we are asking you," she said. "Because she needs so much blood, they will have to take about half of your blood. And that's very dangerous for you. In fact, you might die."

The Daddy's mouth fell open.

"Die?"

"Yes," said Mme Ramotswe. "But then you are her father and we know that you would do this thing for your daughter. Now could you come quickly, or it will be too late. Doctor Moghile is waiting."

The Daddy opened his mouth, and then closed it.

"Come on," said Mme Ramotswe, reaching down and taking his wrist. "I'll help you to the van."

The Daddy rose to his feet, and then tried to sit down again. Mme Ramotswe gave him a tug.

"No," he said. "I don't want to."

"You must," said Mma Ramotswe. "Now come on."